JP6597153B2 - Operating state determination device - Google Patents

Description

  The present invention relates to a driving state determination device that determines a driving state of a driver.

  Conventionally, a driving state of a driver who drives a vehicle is determined. For example, in Patent Document 1, when the vehicle is approaching a preceding vehicle traveling forward, the driver is in a state of reduced consciousness when the driver is in a non-operation state based on the steering angle of the steering wheel of the vehicle. An apparatus for determining that it is present is disclosed.

JP 2012-234290 A

  However, as shown in Patent Document 1, when the driving state is determined based on the steering angle, there is a problem in that the driving state cannot be accurately determined depending on the shape of the road.

  Further, as a method of determining the driving state of the driver, a method of determining the driving state based on physiological information such as the driver's brain wave or electrocardiogram can be considered. In such a method, if a dedicated sensor is attached to the driver, there is a possibility that the driving operation may be hindered. Therefore, it is necessary to acquire physiological information by a non-contact method. However, if physiological information is acquired in a non-contact manner, physiological information cannot be acquired with high accuracy, and as a result, a problem that the driving state cannot be determined with high accuracy arises.

  Therefore, the present invention has been made in view of these points, and an object thereof is to provide a driving state determination device that can accurately determine the driving state of a driver.

  The driving state determination device according to the present invention includes a measuring unit that measures a relative speed between the host vehicle and a preceding vehicle traveling in front of the host vehicle, and an acceleration of the host vehicle, and a position where the preceding vehicle has passed. A first calculating means for calculating an inter-vehicle time indicating a time for the host vehicle to reach, and a second calculator for calculating a margin for maintaining the inter-vehicle time based on the inter-vehicle time, the relative speed, and the acceleration of the host vehicle. A calculating unit; and a determining unit that determines a driving state of the driver of the host vehicle based on the margin.

  By doing in this way, since the driving state determination device can determine whether or not the driver is following the preceding vehicle appropriately based on the margin for maintaining the inter-vehicle time, Regardless of the shape of the road, the driving state of the driver can be accurately determined. In addition, since the relative speed with respect to the preceding vehicle, the inter-vehicle time, and the acceleration of the host vehicle can be stably acquired, the driving state determination device uses physiological information such as a driver's brain wave or electrocardiogram in a non-contact manner. Compared to the above, the driving state of the driver can be determined with high accuracy.

The driving state determination device further includes detection means for detecting a change state of the inter-vehicle time based on the margin, and the determination means is configured to detect the driver based on the change state detected by the detection means. The driving state may be determined.
By doing in this way, the driving state determination device, for example, in response to detecting that the change state of the inter-vehicle time is shorter than the inter-vehicle time with a high collision risk, the driving state of the driver is It can be determined that the degree of arousal has been reduced.

The operating state determination device further includes third calculation means for calculating a plurality of standard deviations of the margins calculated by the second calculation means within a predetermined time, and the determination means is based on the standard deviation. The driving state of the driver may be determined.
When the standard deviation is large, the change in the margin is large, the inter-vehicle time between the host vehicle and the preceding vehicle is not kept constant, and there is a high possibility that the driver cannot properly follow the preceding vehicle. Therefore, the driving state determination apparatus can determine that the driving state of the driver is a state in which the arousal level is reduced based on the standard deviation.

The measurement unit may measure a steering angle of the host vehicle, and the determination unit may determine the driving state of the driver based on the margin and the change in the steering angle.
By doing in this way, the driving state determination apparatus can determine the driving state of the driver based on the change in the steering angle even when there is no preceding vehicle.

  According to the present invention, it is possible to accurately determine the driving situation of the driver.

It is a figure which shows the structure of a driving | running state determination apparatus. It is a flowchart which concerns on determination of a driving | running state. It is a flowchart which shows the flow of the determination process based on a margin.

[Configuration of Driving State Determination Device 10]
Hereinafter, the driving | running state determination apparatus 10 which concerns on one Embodiment of this invention is demonstrated. FIG. 1 is a diagram illustrating a configuration of the driving state determination device 10. The driving state determination device 10 is mounted on a host vehicle 1 equipped with, for example, a constant speed travel / inter-vehicle distance control device (ACC: Adaptive Cruise Control), and determines a driving state of a driver driving the host vehicle 1. It is.

  As shown in FIG. 1, the driving state determination device 10 measures the relative speed between the host vehicle 1 traveling in the direction of the arrow and the preceding vehicle 2 traveling in front of the host vehicle 1 and the acceleration of the host vehicle 1. Then, the inter-vehicle time indicating the time for the host vehicle 1 to reach the position where the preceding vehicle 2 has passed is calculated. When the ACC is not operating, the driving state determination device 10 determines the driving state of the driver of the host vehicle 1 based on the inter-vehicle time, the relative speed, and the acceleration of the host vehicle.

  In the present embodiment, the driving state of the driver of the host vehicle 1 will be described as determining the state of low wakefulness (the state of low wakefulness). It also includes the state of being present and the state of lack of concentration.

As shown in FIG. 1, the driving state determination device 10 includes a speed sensor 11, an acceleration sensor 12, a preceding vehicle detection sensor 13, a steering angle sensor 14, a storage unit 15, and a control unit 16.
The speed sensor 11 detects the vehicle speed of the host vehicle 1 and outputs the detected vehicle speed to the control unit 16.
The acceleration sensor 12 detects the acceleration of the host vehicle 1 and outputs the detected acceleration to the control unit 16. In the present embodiment, the acceleration sensor 12 outputs a positive value when the host vehicle 1 is accelerated, and outputs a negative value when the host vehicle 1 is decelerated.

  The preceding vehicle detection sensor 13 is, for example, a millimeter wave radar. The preceding vehicle detection sensor 13 detects the preceding vehicle 2 by irradiating a millimeter wave in front of the host vehicle 1 and receiving the millimeter wave (reflected wave) reflected by the preceding vehicle 2 traveling in front of the host vehicle 1. To do.

The preceding vehicle detection sensor 13 measures the relative speed between the host vehicle 1 and the preceding vehicle 2 based on the frequency of the irradiated millimeter wave and the frequency of the received reflected wave. The preceding vehicle detection sensor 13 measures the relative distance between the host vehicle 1 and the preceding vehicle 2 based on the time from when the millimeter wave is applied until the reflected wave is received. The preceding vehicle detection sensor 13 outputs the measured relative speed and relative distance to the control unit 16. Further, when the preceding vehicle 2 is not detected, the preceding vehicle detection sensor 13 outputs non-detection information indicating that the preceding vehicle 2 is not detected to the control unit 16. In the present embodiment, the relative speed indicates a positive value when the vehicle speed of the host vehicle 1 is higher than the vehicle speed of the preceding vehicle 2, and the vehicle speed of the host vehicle 1 is lower than the vehicle speed of the preceding vehicle 2. , Shall indicate a negative value.
The steering angle sensor 14 detects the steering angle of a handle provided in the host vehicle 1 and outputs the detected steering angle to the control unit 16.

The storage unit 15 is, for example, a ROM, a RAM, or a hard disk. The storage unit 15 stores various programs for causing the control unit 16 to function. The storage unit 15 stores information acquired by the control unit 16 from various sensors and information calculated by the control unit 16 itself.
The control unit 16 is a CPU, for example. As shown in FIG. 1, the control unit 16 includes a measurement unit 161, a first calculation unit 162, a second calculation unit 163, a detection unit 164, a third calculation unit 165, a fourth calculation unit 166, A determination unit 167 and an output unit 168 are provided.

  The measurement unit 161 acquires various information output from the speed sensor 11, the acceleration sensor 12, the preceding vehicle detection sensor 13, and the steering angle sensor 14, whereby the relative speed between the own vehicle 1 and the preceding vehicle 2, the own vehicle The relative distance between the vehicle 1 and the preceding vehicle 2, the vehicle speed of the host vehicle 1, the acceleration of the host vehicle 1, and the steering angle of the host vehicle 1 are measured. The measurement unit 161 measures the relative speed, the relative distance, the vehicle speed of the host vehicle 1, and the acceleration of the host vehicle 1 periodically (for example, every 10 seconds).

  The first calculation unit 162 calculates an inter-vehicle time indicating a time for the host vehicle 1 to reach a position where the preceding vehicle 2 has passed. Specifically, the first calculation unit 162 calculates the inter-vehicle time by dividing the relative distance measured by the measurement unit 161 by the speed of the host vehicle 1.

The second calculation unit 163 calculates a margin for maintaining the inter-vehicle time based on the inter-vehicle time calculated by the first calculation unit 162, the relative speed measured by the measurement unit 161, and the acceleration of the host vehicle 1. The second calculation unit 163 calculates a margin for maintaining the inter-vehicle time based on the following equation (1). In the following description, the margin for maintaining the inter-vehicle time is simply referred to as “margin”. Further, in the expression (1), a value obtained by dividing each term by the vehicle speed of the host vehicle 1 may be used as a margin.
Margin == Relative speed−Inter-vehicle time × Acceleration of own vehicle 1 (1)

  In this embodiment, when the vehicle speed of the own vehicle 1 is smaller than the vehicle speed of the preceding vehicle 2, that is, when the own vehicle 1 moves away from the preceding vehicle 2, the relative speed shows a negative value. As the vehicle speed becomes higher than the vehicle speed of the host vehicle 1, the margin increases.

  Further, when the host vehicle 1 is decelerated by the driver operating the brake or the like, the acceleration of the host vehicle 1 becomes a negative value and the margin increases. Further, when the host vehicle 1 is accelerating by the driver operating the accelerator, the acceleration becomes a positive value and the margin is reduced.

  When the relative speed is 0 and the host vehicle 1 is traveling at a constant speed, the inter-vehicle time does not change and the margin is 0. Further, when the margin is a negative value, it indicates that the inter-vehicle time is shortened, and when the margin is a positive value, it indicates that the inter-vehicle time is increased.

  The detection unit 164 detects the change state of the inter-vehicle time based on the margin calculated by the second calculation unit 163. For example, when the margin indicates a negative value, it indicates that the inter-vehicle time is shortened and the risk of collision is increasing. For this reason, when the margin is a negative value, the detection unit 164 detects that the inter-vehicle time has changed to a situation in which the collision risk has increased (dangerous situation).

The third calculation unit 165 calculates standard deviations of a plurality of margins calculated by the second calculation unit 163 within a predetermined time (for example, within one minute).
The fourth calculation unit 166 performs FFT (Fast Fourier Transform) on the steering angle measured by the measurement unit 161 within a predetermined time, and calculates the power spectral density (PSD) of the steering angle. Note that the fourth calculation unit 166 calculates the power spectral density of the steering angle based on the steering angle measured by the measurement unit 161 within a predetermined time. However, the present invention is not limited to this, and the time has a length different from the predetermined time. Alternatively, the power spectral density of the steering angle may be calculated based on the steering angle measured by the measuring unit 161.

The determination unit 167 determines the driving state of the driver based on the margin calculated by the second calculation unit 163 and the change in the steering angle measured by the measurement unit 161.
Specifically, when the ACC is not operating and the preceding vehicle detection sensor 13 detects the preceding vehicle 2, the determination unit 167 automatically determines whether the second calculating unit 163 has calculated the margin. The driving state of the driver of the vehicle 1 is determined. More specifically, the determination unit 167 determines whether or not the driving state of the driver of the host vehicle 1 is a state of reduced alertness based on the change state of the inter-vehicle time detected by the detection unit 164. For example, if the determination unit 167 detects that the change state of the inter-vehicle time has become a dangerous state within a predetermined time a predetermined number of times, the driving state of the driver of the host vehicle 1 is in a state of reduced alertness. Is determined.

  In addition, when the ACC is not operating and the preceding vehicle detection sensor 13 detects the preceding vehicle 2, the determination unit 167 operates based on the standard deviation calculated by the third calculation unit 165. Determine the state. Specifically, when the standard deviation calculated by the third calculation unit 165 is greater than a first threshold value set in advance, the determination unit 167 determines that the driving state of the driver is a state of reduced arousal level.

  In addition, when the ACC is operating, or when the preceding vehicle detection sensor 13 does not detect the preceding vehicle, the determination unit 167 is based on the change in the steering angle measured by the measuring unit 161. Determine the operating state. For example, in the power spectrum density calculated by the fourth calculation unit 166, the determination unit 167 has a power spectrum density in a predetermined frequency band (for example, 0.05 to 0.15 Hz) that is equal to or greater than a predetermined second threshold value. Furthermore, it is determined that the driving state of the driver is a state of reduced arousal level.

  It should be noted that the determination unit 167 does not drive the driver based on the change in the steering angle measured by the measurement unit 161 even when the ACC is not operating and the preceding vehicle detection sensor 13 detects the preceding vehicle 2. The state may be determined.

  The output unit 168 outputs warning information when the determination unit 167 determines that the driving state of the driver is a state of reduced alertness. For example, the output unit 168 causes a sound output unit (not shown) such as a speaker provided in the host vehicle 1 to output a warning sound indicating that the degree of arousal is low and is in a dangerous state. The output unit 168 may cause the sound output unit to output a sound that prompts the driver to take a break.

[Flowchart for determination of driving state]
Then, the flow of the process which the driving | running state determination apparatus 10 performs is demonstrated. FIG. 2 is a flowchart showing a processing procedure when the driving state determination device 10 determines the driving state.

  First, the measurement unit 161 includes the relative speed between the host vehicle 1 and the preceding vehicle 2, the relative distance between the host vehicle 1 and the preceding vehicle 2, the vehicle speed of the host vehicle 1, the acceleration of the host vehicle 1, and the steering angle of the host vehicle 1. Is measured (S10).

  Subsequently, the determination unit 167 determines whether or not the ACC is operating (S20). When determining that the ACC is operating, the determining unit 167 moves the process to S50, and when determining that the ACC is not operating, the determining unit 167 moves the process to S30.

In S <b> 30, the determination unit 167 determines whether the preceding vehicle 2 exists based on the detection status of the preceding vehicle detection sensor 13. When determining that the preceding vehicle 2 is present, the determining unit 167 moves the process to S40, and when determining that the preceding vehicle 2 is not present, the determining unit 167 moves the process to S50.
In S40, the determination unit 167 performs a determination process based on the margin. Details of this processing will be described later.

In S50, the fourth calculation unit 166 calculates the power spectral density (PSD) of the steering angle measured by the measurement unit 161 from a predetermined time before the current time to the current time.
Subsequently, the determination unit 167 determines whether or not the power spectral density at the predetermined frequency is equal to or higher than a predetermined second threshold (S60). If the determination unit 167 determines that the power spectral density is equal to or higher than a predetermined second threshold, the determination unit 167 proceeds to S70 and determines that the driving state of the driver is a state of reduced alertness.
If the determination unit 167 determines that the power spectral density is less than a predetermined second threshold, the process proceeds to S80.

  In S80, the output unit 168 determines whether or not it is determined that the driving state of the driver is a state of reduced alertness. If the output unit 168 determines that the state is a state of reduced arousal level, the process proceeds to S90 and outputs warning information, and then the process proceeds to S10. If it is determined that the awakening level is not reduced, the output unit 168 moves the process to S10.

[Flowchart for determination processing based on margin]
Next, details of the determination process based on the margin will be described. FIG. 3 is a flowchart showing a procedure of determination processing based on the margin.

First, the first calculation unit 162 calculates the inter-vehicle time by dividing the measured relative distance by the measured vehicle speed of the host vehicle 1 (S41).
Subsequently, the second calculation unit 163 calculates a margin based on the measured relative speed, the measured acceleration of the host vehicle 1, and the calculated inter-vehicle time (S42).

  Subsequently, the detection unit 164 determines whether or not the inter-vehicle time is a situation (dangerous situation) in which the collision risk is increased based on the calculated margin (S43). If the detection unit 164 determines that it is a dangerous situation, it moves the process to S44, and if it determines that it is not a dangerous situation, it moves the process to S46.

  In S <b> 44, the determination unit 167 determines whether or not the dangerous situation from the predetermined time before the current time to the current time has been detected a predetermined number of times or more. If the determination part 167 determines with having detected more than predetermined times, it will transfer a process to S45 and will determine with a driver | operator's driving state being a state of arousal level reduction. If the determination unit 167 determines that the number of detections of the dangerous situation is less than the predetermined number, the process proceeds to S46.

In S46, the third calculation unit 165 calculates standard deviations of a plurality of margins calculated by the second calculation unit 163 from a predetermined time before the current time to the current time.
Subsequently, the determination unit 167 determines whether or not the calculated standard deviation is greater than or equal to a predetermined first threshold value (S47). If it determines with it being more than a 1st threshold value, the determination part 167 will transfer a process to S45 and will determine with the driving | running state of a driver | operator being a wakefulness fall state. Moreover, if the determination part 167 determines with less than a 1st threshold value, the process which concerns on this flowchart will be complete | finished.

[Effect in this embodiment]
As described above, the driving state determination device 10 includes the measurement unit 161 that measures the relative speed between the host vehicle 1 and the preceding vehicle 2 and the acceleration of the host vehicle 1, and the inter-vehicle time between the host vehicle 1 and the preceding vehicle 2. A first calculation unit 162 for calculating the vehicle time, a second calculation unit 163 for calculating a margin for maintaining the inter-vehicle time based on the inter-vehicle time, the relative speed, and the acceleration of the host vehicle 1; And a determination unit 167 that determines the driving state of the driver of the vehicle 1.

  By doing in this way, the driving | running state determination apparatus 10 can determine whether the driver | operator is following the preceding vehicle 2 appropriately based on the margin which maintains the time between vehicles. Therefore, the driving state of the driver can be accurately determined regardless of the shape of the road. Further, since the relative speed with respect to the preceding vehicle 2, the inter-vehicle time, and the acceleration of the host vehicle 1 can be stably acquired, the driving state determination device 10 uses physiological information such as a driver's brain wave and electrocardiogram in a non-contact manner. The driving state of the driver can be determined with higher accuracy than in the case of using.

  Further, since the driving state determination device 10 determines the driving state of the driver based on the change state of the inter-vehicle time detected by the detection unit 164, for example, the change state of the inter-vehicle time is a situation where the collision risk is increased (danger It can be determined that the driving state has become a state of reduced arousal level in response to detecting that the situation has been reached.

The driving state determination device 10 further includes a third calculation unit 165 that calculates the standard deviation of the margin calculated by the second calculation unit 163 within a predetermined time, and the determination unit 167 is based on the standard deviation. The operation state of is determined.
When the standard deviation is large, there is a large change in the margin, the inter-vehicle time between the host vehicle 1 and the preceding vehicle 2 is not kept constant, and the driver may not be able to properly follow the preceding vehicle 2 Is expensive. Therefore, the driving | running state determination apparatus 10 can determine that a driver | operator's driving state is a wakefulness fall state based on a standard deviation.

  In addition, since the driving state determination device 10 determines the driving state of the driver based on the margin and the change in the steering angle, the driver based on the change in the steering angle even when the preceding vehicle 2 does not exist. Can be determined.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  In the above-described embodiment, the driving state determination device 10 has been described as being mounted on the host vehicle 1 including the ACC, but is not limited thereto. The driving | running state determination apparatus 10 may be mounted in the own vehicle 1 which is not equipped with ACC. In this case, the driving state determination device 10 may always perform the determination process based on the margin when the preceding vehicle 2 exists.

DESCRIPTION OF SYMBOLS 1 Own vehicle 2 Leading vehicle 10 Driving state determination apparatus 11 Speed sensor 12 Acceleration sensor 13 Leading vehicle detection sensor 14 Steering angle sensor 15 Storage part 16 Control part 161 Measurement part 162 1st calculation part 163 2nd calculation part 164 Detection part 165 1st 3 calculation unit 166 4th calculation unit 167 determination unit 168 output unit

Claims (4)

A measuring means for measuring a relative speed between the host vehicle and a preceding vehicle traveling in front of the host vehicle, and an acceleration of the host vehicle;
First calculation means for calculating an inter-vehicle time indicating a time for the host vehicle to reach a position where the preceding vehicle has passed;
Second calculating means for calculating a margin indicating a magnitude of a risk that the own vehicle collides with the preceding vehicle based on the inter-vehicle time, the relative speed, and the acceleration of the own vehicle ;
Determination means for determining a driving state of a driver of the host vehicle based on the margin;
Equipped with a,
The margin is
Margin == Relative speed−Inter-vehicle time × Acceleration of own vehicle
An operating state determination device calculated as: Further comprising detection means for detecting a change state of the inter-vehicle time based on the margin.
The determination means determines the driving state of the driver based on the change state detected by the detection means.
The driving | running state determination apparatus of Claim 1. A third calculating means for calculating a plurality of standard deviations of the margins calculated by the second calculating means within a predetermined time;
The determination means determines the driving state of the driver based on the standard deviation.
The driving | running state determination apparatus of Claim 1 or 2. The measuring means measures a steering angle of the host vehicle;
The determination means determines the driving state of the driver based on the margin and the change in the steering angle.
The driving | running state determination apparatus of any one of Claim 1 to 3.

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